Interleukin-36-receptor antagonist deficiency and generalized pustular psoriasis.

BACKGROUND: Generalized pustular psoriasis is a life-threatening disease of unknown cause. It is characterized by sudden, repeated episodes of high-grade fever, generalized rash, and disseminated pustules, with hyperleukocytosis and elevated serum levels of C-reactive protein, which may be associated with plaque-type psoriasis. METHODS: We performed homozygosity mapping and direct sequencing in nine Tunisian multiplex families with autosomal recessive generalized pustular psoriasis. We assessed the effect of mutations on protein expression and conformation, stability, and function. RESULTS: We identified significant linkage to an interval of 1.2 megabases on chromosome 2q13-q14.1 and a homozygous missense mutation in IL36RN, encoding an interleukin-36-receptor antagonist (interleukin-36Ra), an antiinflammatory cytokine. This mutation predicts the substitution of a proline residue for leucine at amino acid position 27 (L27P). Homology-based structural modeling of human interleukin-36Ra suggests that the proline at position 27 affects both the stability of interleukin-36Ra and its interaction with its receptor, interleukin-1 receptor-like 2 (interleukin-1 receptor-related protein 2). Biochemical analyses showed that the L27P variant was poorly expressed and less potent than the nonvariant interleukin-36Ra in inhibiting a cytokine-induced response in an interleukin-8 reporter assay, leading to enhanced production of inflammatory cytokines (interleukin-8 in particular) by keratinocytes from the patients. CONCLUSIONS: Aberrant interleukin-36Ra structure and function lead to unregulated secretion of inflammatory cytokines and generalized pustular psoriasis. (Funded by Agence Nationale de la Recherche and Société Française de Dermatologie.).

Squamous cell carcinoma complicating recessive dystrophic epidermolysis bullosa-Hallopeau-Siemens: a report of four cases.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB), an autosomal-recessive genodermatosis, is one of the more severe forms of the epidermolysis bullosa dystrophica group, and is characterized by generalized blistering of the skin and mucous membranes. Cutaneous squamous cell carcinoma is one of the most serious complications of this disease. METHODS: We report four patients (three females and one male), two of whom were under 20 years of age, suffering from RDEB-Hallopeau-Siemens. RESULTS: All patients developed well-differentiated squamous cell carcinoma. No metastases were detected. All cases were treated surgically. Fatal evolution was noted in one patient. A second tumor was detected in another patient during the follow-up period. No further tumors or metastases were observed in the other patients. CONCLUSIONS: Regular clinical and histologic examination of any nodular lesions or non healing ulcers of all patients suffering from RDEB-Hallopeau-Siemens to detect an early malignancy is recommended.